1. Field of the Invention
This invention relates generally to processing of blood substances; and more particularly to disinfecting red blood cells and subsequently removing the disinfectant from the red blood cells.
This processing is designed to inactivate or greatly reduce the activity of certain harmful contaminants, thus rendering the blood cells safe for human therapeutic use. Such harmful contaminants include, but are not limited to, several blood-borne viruses and other microorganisms that are known to cause or suspected of causing AIDS, the various known forms of viral hepatitis, cytomegalovirus, and Epstein-Barr virus.
2. Prior Art
Even though human blood is supplied for transfusion purposes very commonly, there has been no way to guarantee the safety of human blood for transfusion. There is thus an important need to make human blood a safe product.
Transfusion of human blood--particularly its red-blood-cell component--carries a well-known risk for transmitting viruses, including the hepatitis B virus; the non-A, non-B hepatitis virus or viruses; and the HTLV-III virus. HTLV-III is a human retrovirus which has been implicated in AIDS (see Gallo, R. C. et al.).
Detection and isolation of cytopathic retroviruses (HTLV-III) from patients with AIDS, and certain members of groups at high risk for AIDS, have been frequently reported. One such report appears in Science 1984; 224:500-3.
For further corroboration of these findings, see Sarin, P. S. et al., Human T-Lymphotrophic Retroviruses in Adult T-cell Leukemia-Lymphoma and Acquired Immune Deficiency Syndrome, J. Clinical Immunol. 1984; 4:415-23; and Wong-Staal, F., Gallo, R. C., Human T-Lymphotrophic Retroviruses, Nature 1985; 317:395-402.
Development of new disinfectants and automated cell washers (e.g., the IBM Cell Washer) that can wash red blood cells has created new possibilities for sterilizing human blood components to allow safe transfusion. In particular, Sarin et al. have reported that a laboratory disinfectant composed of approximately 0.23 percent sodium chlorite and 1.26 percent lactic acid (LD.TM. Alcide, Norwalk, Conn.) at a dilution of 1:200 or less can completely inactivate the HTLV-III/HIV virus (see New Engl. J. Med. 1985; 313:1416). That disinfectant corresponds to the teachings of Howard Alliger's U.S. Pat. No. 4,084,747 and Re. No. 31,779, whose teachings are hereby incorporated by reference.
It has not been practical, however, to treat human blood with disinfectant, as this process has been too toxic to red blood cells. In particular, hemolysis resulted.
Thus no process to eliminate or lessen the transmission of harmful contaminants in transfusion of human blood has been available.